Device for welded joints in pipework

Abstract

A piping device that includes two parts, each consisting of two concentric rings joined together by a solid steel mantle that when assembled produce a confined space between the pieces of at least 50 mm and house a guide wedge and an elastomeric ring that It produces the hydraulic seal and the thickness of this solid steel mantle and the assembly area between the cavity and the guide wedge is at least twice the thickness of the pipe. The heat of the welding process between the external concentric rings is released by the device itself and the temperature inside the pipe does not exceed 120°+/−20° C., eliminating any possible internal corrosion in the areas of the welded joints, since it prevents damage to the internal lining and increases the useful life of the pipe during it operation.

The invention claimed is: 
     
       1. A device to be installed in pipes, that eliminates internal corrosion in the welded joints because it prevents the damage of the welding heat to the inner coating of said pipes by dissipating it naturally and spontaneously, comprising a first part ( 1 ) which is assembled to a second part ( 2 ) producing a confined space ( 51 ) where both parts ( 1  and  2 ) are formed by two concentric rings, an inner ring ( 4 ,  21 ) of the same diameter as the pipe ( 38 ), and an outer ring ( 3 ,  20 ) with the rings joined together by a solid steel mantle ( 5 ,  22 ); the inner ring ( 4 ) has a cavity ( 8 ) where a guide wedge ( 29 ) of the inner ring ( 21 ) is assembled and at the bottom of the cavity ( 8 ) of the first part ( 1 ) there is a concavity ( 9 ) to accommodate an fluor elastomer ring ( 45 ) and at the end of the guide wedge ( 29 ) of the second part ( 2 ) there is a concavity ( 30 ) confining said ring of fluor elastomer ( 45 ) to the concavity ( 9 ), and the inner area of the contact surfaces ( 39 ) between the inner rings ( 4 ,  21 ) are protected with a highly adhesive epoxy seal, a separation of 2 to 3 millimeters ( 46 ) is achieved between the outer rings ( 3 ,  20 ) where the welded joint ( 44 ) is done, wherein the width ( 10 ,  23 ) of the solid steel mantle ( 5 ,  22 ) that separates the inner and outer rings of the first part and the second part is at least 50 mm and the thickness ( 14 ,  24 ) of this solid steel mantle ( 5 , 22 ) as well as the thickness of the assembly area ( 52 ) between the cavity ( 8 ) of part ( 1 ) and the guide wedge ( 29 ) of part ( 2 ) is at least twice the thickness of the pipe ( 40 ,  41 ). 
     
     
       2. The device according to  claim 1 , wherein the inner ring ( 4 ) has a minimum width ( 12 ) corresponding to 30 millimeters plus twice the thickness of the pipe ( 40 ,  41 ) plus the width of a welding neck ( 18 ). 
     
     
       3. The Device according to  claim 1 , wherein the inner ring ( 21 ) has a minimum width ( 32 ) corresponding to the width of the guide wedge ( 29 ) plus 20 mm, plus twice the thickness of the pipe ( 40 ,  41 ) plus the width of a welding neck ( 26 ). 
     
     
       4. The device according to  claim 1 , wherein the outer rings ( 3  and  20 ) have a minimum outer diameter ( 11  and  33 ) equivalent to the inner diameter of the pipe ( 38 ) plus 100 millimeters, plus 6 times the pipe thickness ( 40 ,  41 ) and the minimum width ( 16  and  34 ) of these rings is at least 23.5 millimeters plus twice the thickness of the pipe ( 40 ,  41 ). 
     
     
       5. The device according to  claim 1 , wherein the ring of fluor elastomer ( 45 ) remains compressed between the concavity ( 9 ) of the first part ( 1 ) and the concavity ( 30 ) of the second part ( 2 ). 
     
     
       6. The device according to  claim 1 , wherein the contact area ( 39 ) of both faces of the inner rings ( 4 ,  21 ) where the epoxy seal is applied has a minimum separation of 0.5 millimeters with a maximum clearance of +/−20% which prevents electrical contact between the faces forming a crevice ( 47 ), preventing crevice corrosion in the device.